So it's a viable buisness idea then, and the military would be interested in possible funding? let alone NASA. R and D costs could be about a Billion tops, then each indivicual unit would be about a billion or so to build. Expensive but realitivly not too bad.

As to a viable business project and military interest, do a search for ATG Skycat and WALRUS.

The technology is already done, the engines were made in prototype i nthe 60s, but stopped evelopement on them becasue they were too politicly contriversail. Only R and D would be incrasing egine effiacny then designing the dropship.

One draw back is due to the immense weight of the dropship, it can only land and take off in certain palces without the landing legs getting to stuck in the ground.

So here is some more information. What i need from you guys is wether or not this concept would be viable in military operations.

 

SOo first off here is some info on the engins and the ship desgin. Ship design is roughly spheroid, about 18-220meters high, 190-250meters wide at it's widest point. So this things massive. Gross weight is aobut 30,000 tons.

 

Here is some ifnormation on similar designed engines.

 

"In this section I describe a huge nuclear powered rocket launcher. I will repeat and expand upon many of the points I made above, because I don't want to throw cryptic acronyms around. I want people to understand just how powerful we can make this rocket if we decide to do it.

The effective use of nuclear power in space transportation allows a paradigm shift in our thinking. All boosters which have been built to date have been shackled by the low efficiency of chemical fuels. Using chemicals it is possible to get off earth, but only barely. Every gram of structure must be trimmed, exotic materials and cutting-edge techniques are a necessity, and safety margins must be as slim as we dare if success is to be achieved.

Nuclear power changes all that. Nuclear is VASTLY more energetic than chemical. We no longer must guard every gram of mass. Much more "margin" can be included. Much more safety can be designed into the machine.

Let's examine a large heavy lift booster. There are other kinds of nuclear rockets we could build, but we desperately need a heavy lift booster if we are to excite people, catch their dreams, and actually do big stuff in space.


For an engine, I will designate a Gaseous Core Nuclear Reactor design, of the Nuclear Lightbulb subvariant. I like the gas core design for a number of reasons, and the nuclear lightbulb variant for several more.

To recap, the efficiency and power of the thruster is based on the difference in temperature between the fissioning mass and the reaction mass. If you run a solid core NTR much above 3000 C, it melts. This provides a firm "ceiling" on how efficient a solid core reactor can be. A gas core design STARTS melted. In addition, since all of the structure of the fuel mass is dynamic, a gas cored reactor is inherently safer than a solid core device. If a "hot spot" develops in a solid core, disaster ensues. If a hot spot develops in a gas core, the hot spot superheats and "puffs" itself out of existence. A gas core reactor is expected to operate at temperatures of 25,000C. The much higher temperature gradient makes the thruster inherently more efficient.

Second, a solid core reactor has a "fixed" core, since it is solid. A gas core reactor does not, and the radioactive fuel is easily "sucked" out of the core and stored in a highly non-critical state completely out of the engine! The fuel storage system I propose is a mass of thick walled boron-aluminum alloy tubing. As I said above, the fuel proper is uranium hexaflouride gas. UF6 is mean stuff, but we have decades of experience handling it in gaseous diffusion plants, and common aluminum and standard seals are available which resist attack from it. It is stoichiometric, fluorine is low activation, and UF6 changes phase at moderate temperatures, allowing it to be converted from high pressure gas to a solid and back again using nothing fancier than gas cooling and electrical heaters. This naturally makes dealing with the engine easier.

In addition, the design of the gas core allows the addition and removal of fuel "on the fly." The core can also have its density varied by control of the vortex, which directly affects criticality. Both of these elements allow very potent control inputs to be applied to a gas core reactor which are very stable and unaffected by the isotopic condition of the fuel mass.

Also, to repeat, due to the extremely high temperature gradient in the motor, the main cooling of the fissioning mass is not conductive but radiative, a mode which is inherently less susceptible to perturbations. (Having no working fluid for cooling means no material characteristics for the working fluid must be considered.) This radiative cooling mechanism is what allows the "lightbulb" system to work. The silica bulb just has to be transparent enough to let the gigantic power output of the fissioning core flow through, while keeping the radioactive material of the core safely contained inside the thruster. No radioactive materials leak out of the exhaust, it is completely "clean."

Third, a gas cored reactor has several potential "scram" modes, both fast and slow, and the speed of the reaction is easily "throttled" by adding and removing fuel or by manipulating the vortex. A 'scram' is an emergency shutdown, usually done in a very fast way. For example: a gas cored reactor can be fast scrammed by using a pressurized "shotgun" behind a weak window. If the core exceeds the design parameters of the window, which are to be slightly weaker than the silica "lightbulb," then the "shotgun" blasts 150 or so kilos of boron/cadmium pellets into the uranium gas, quenching the reaction immediately. A slightly slower scram which is implemented totally differently is to vary the gas jets in the core to instill a massive disturbance into the fuel vortex. This disturbance would drastically reduce criticality in the fission gas. A third scram mode, slightly slower still, is to implement a high-speed vacuum removal of the fuel mass into the storage system. Having three separate scram modes, one of which is passively triggered, should instill plenty of safety margin in the nuclear core of each thruster.
Extensive work was done on gas core reactors, and 25 years ago several experimental designs were built and run successfully. There were technical challenges, but nothing that seems insurmountable or even especially difficult given our current computer and material skills.

The engine I propose is this:

A Gas cored NTR using a silica lightbulb. The silica bulb is cooled and pressure-balanced against the thrust chamber by high pressure hydrogen gas. The cooling gas from the silica bulb is used to power three turbopumps "borrowed" from the Space Shuttle Main Engine. These pumps are run at a very relaxed 88 percent of rated power at their maximum setting. The three pumps move 178 kilos of liquid hydrogen per second combined. Most of this is sprayed into the thrust chamber. A portion of the liquid hydrogen is forced into cooling channels for the thrust chamber and expansion nozzle, where a portion of it is bled from micropores to form a cooling gas layer. The gaseous hydrogen that is not bled then flows down the silica lightbulb to cool it, and the cycle finally goes into powering the turbopumps.

This engine produces 6,000,000 pounds of thrust, with an exhaust velocity of 30,000 meters per second, from a thermal output of approximately 400 gigawatts. This equates to an Isp of 3060 seconds. Several sources state that a gas core NTR can exceed 5000 seconds Isp, so 3060 is well inside the overall performance envelope. The three turbopumps from the SSME are run at low power levels, and even losing a pump allows the engine to continue running as long as there is no damage to the nuclear core. Lets assume this design is able to achieve a thrust to weight ratio of ten to one, so the engine and all of its safety systems, off-line fuel storage, etc, weighs 600,000 pounds. We can build this engine easily for 300 tons." - link

 

So since our ship weighs a good, 30,000 short tons we will need at least 10 engins. We will use 14 engines.

We now have a total possible lift off capacity of 42,000 tons of thrust.

 

 

Let's design the vehicle for a total DeltaV of 15 km per second. This is very high for a LEO booster, but the reason for it is to allow enough reaction mass to perform a powered descent. In other words, this is a true spaceship, that flies up and then can fly back down again.

 

Now lets find out how much fuel we need.

The formula to calculate DeltaV from a rockets mass is:
DeltaV = c * ln(M0/M1).

'c' is exhaust velocity of the engines and equals 30,000 m/s.
'ln' is the natural log.
'M0' is the initial mass of the vehicle, and we have set this to be 60 million pounds.
'M1' is the mass of the vehicle when it runs dry of reaction mass.

The value of M1 is what we need to find, since we know we want a total DeltaV of 15,000 m/s.
Let's design the vehicle for a total DeltaV of 15 km per second. This is very high for a LEO booster, but the reason for it is to allow enough reaction mass to perform a powered descent. In other words, this is a true spaceship, that flies up and then can fly back down again.

 

Doing a little simple math, we find we need 24,000,000 pounds of reaction mass. Since we are using liquid hydrogen, we can now calculate the size of the hydrogen tank needed, which is 152,000 cubic meters.  Now we have 24 million pounds + engins which are 14*300tons= 8.4 million pounds. So our ship is now 32.4 out of a total 60 million pounds. Now we build the body of the ship 8 million pounds would be a considerable amount for the pure body. So now we have 29.8 million pounds left. We now add 10 million poudns of armor, internal structure. We now have 9.8 MILLION POUNDS or 4 900 short tons left for cargo. So lets add ONE THOUSAND TONS of weapons, jamming systems, elctronic warfare systems, and self-defense systems. Another 900 tons for miscelnaious things not coverd in this breif example. And due to my generous giving of stuff at the very minimum this ship will have 3 thousnd tons of cargo and is an armoured behemoth which is armed to the teeth.

 

 

This ship, while being nuclear powerd there is absolutly no polution to the enviorment, no nuclear waste is output by the engines AT ALL.

 

This ship, due to my generous giving of weight has a lot of redundancy and saftey built in. A civillan vesel has a posible maximum lift of about 8 000 tons while still being perfectly safe.

 

 

So would this concept be viable for military operations ? This ship does go oribital so it could be used to take otu enemy satelites with it's weapons systems.

 

 

Armeramnt:

 

This is jsut guessing really but

 

3 Missle launchers each firing  MLRS sized missles.

 

1 Missle launcher firing larger sized missle (Orbit to earch bombardment possible ???)

 

other.

 

 

 

While this plan may sound like something out of science fiction it is viable and possible we are gonna try to have our first ship built by 2020-2025. We're really in prelimenary stages now. Would the military be interested in this ?

 

 

 

 

 

*Note: Sorry for any bad spelling or other erros it's late here.

 

 

 

 

 

can't see the benefit in it.

 

only useful if you have absolute intra-theatre dominance - otherwise it will require disproportionate effort to protect it while in and out bound.

The safety implications are gargantuan. The environmental considerations are massive. On top of this, you need to design and build your vehicle to withstand loads that aren't defined, since we haven't built anything like this before. You would need several sub-scale demonstrators to prove concepts and cooperation from various regulatory authorites to prove it for use. If you think that even a fraction of that could be doen for a mere billion dollars, you are having a laugh. It costs more to develop an aircraft - the F22 cost $43Bn, the A380 cost $15bn, the 787 cost $16-18bn. These are fairly conventional vehicles with well established design rules.

At 15km/s you would need vast heat-shielding from aerothermal effects, other wise you'll end up with a vast, radioactive crater with the liquified remains of the ship and cargo laminated over the top.

You'd make far more money in commercial space launches than a military application

Well maybe your right about that money thing, my freind had not typed in a 0 by accident when he sent me the cost report.

As to vulerability of this ship, it will be heavily armored and protected, so if anyhting does make it through it's AEIGIS type defense system, Phalnax guns (the new oens that track projectiles too,) and possilby laser defeneses. As well as it's Jamming and Electronic warfare systems. it could take a few hits. It will be most vulnerable druign re-entry, but during this time sensors will have a hard time tracking the ship, so it will be much harder for them to hit us.

 

Well maybe your right about that money thing, my freind had not typed in a 0 by accident when he sent me the cost report.

As to vulerability of this ship, it will be heavily armored and protected, so if anyhting does make it through it's AEIGIS type defense system, Phalnax guns (the new oens that track projectiles too,) and possilby laser defeneses. As well as it's Jamming and Electronic warfare systems. it could take a few hits. It will be most vulnerable druign re-entry, but during this time sensors will have a hard time tracking the ship, so it will be much harder for them to hit us.

 

Am I the only one who thinks this is ludicrous?  For a concept that far in advance of anything out there today, it sounds a bit, uh, amateurish.  Kind of like something a high-schooler would sketch during a slow moment in shop class.

nope, I think there are a few of us - its just that we've been polite (kind of)

 

If you can build a vessel with that kind of thrust, and a tenner says you can't, you would be far far far far far far far far far far better off selling it as a commercial launch vehicle or for inter-planetary exploration than as a military white elephant.

1. ORION makes more sense STO.

2. As for advanced airbreather jet engines, I agree with the above commentators that the materials limits are the kicker. An MHD configured compound jet plasma thruster is about the next stage with a ionized layer protection for the aeroshell for the scramjets envisioned.

3. Nuclear lightbulb engine is inferior to M2D2 propulsion or VASIMR and that is only applicable in space.

4. Liquid fuel cored fission reactor rocket in any application is INSANE.

. 

Herald